/**
 * Copyright 2006 Brad Reynolds
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.leeloo.internal.core;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.StructuredSelection;

/**
 * Utility methods for viewers.
 * 
 * @author Brad Reynolds
 */
public class Viewers {
    /**
     * Unpacks the selection and returns the object contained if it is of the
     * requested <code>clazz</code>.
     * 
     * @param selection
     * @param clazz
     * @return selected object, <code>null</code> if not found or of the
     *         incorrect type
     */
    public static Object getSingleSelectedObject(ISelection selection, Class clazz) {
        Object result = null;
        if (selection != null && !selection.isEmpty() && selection instanceof StructuredSelection) {
            StructuredSelection structuredSelection = (StructuredSelection) selection;
            if (structuredSelection.size() == 1 && clazz.isInstance(structuredSelection.getFirstElement())) {
                result = structuredSelection.getFirstElement();
            }
        }

        return result;
    }
}